The present invention relates to generally a clamping device to clamp plate-like members, and more particularly a clamping device for use in clamping together an inner packing box and an outer packing box or a plurality of packing boxes.
In general, packing bands or belts made of steel or synthetic resin have been used for binding the packing boxes. Therefore there is a fear that the packing bands or belts may be loosened or cut off during shipment. When the packing bands or belts are cut off, they cannot be reused.
There has been devised and demonstrated a packing method in which inner and outer boxes are bound together by means of clamping or locking devices attached to the peripheries of the boxes. However, when the clamping or locking devices are broken, the inner and outer boxes cannot be bound together even though they may be used.
There has been also proposed a two-piece shipping clamping device of the type comprising a male and female members. The male member has a large-diameter cylindrical portion with the closed bottom and the flange extending outwardly from the periphery of the open end and a small-diameter cylindrical portion extended from the bottom of the large-diameter cylindrical portion coaxially thereof. At the open end of the small-diameter cylindrical section are attached engaging projections which are angularly spaced apart by 180.degree.. The female member has cylindrical barrel or drawn portion for receiving therein the small-diameter cylindrical portion of the male member, and a flange extending outwardly from the bottom of the cylindrical barrel or drawn portion. A hole with diametrically spaced apart recesses for permitting the insertion of the engaging projections is formed through the bottom of the cylindrical barrel portion of the female member. In packing, the barrel portion of the female member is fitted into the hole formed through the side wall of an inner packing box, and the large-diameter cylindrical portion of the male member is fitted into the hole formed through the side wall of an outer packing box in alignment with the hole of the inner box, in such a manner that the small-diameter cylindrical portion of the male member is fitted into the cylindrical barrel portion of the female member and the engaging projections are inserted through the recesses of the hole formed through the bottom of the female member. Thereafter, one holds a knob formed within the large-diameter cylindrical portion of the male member to rotate the latter through 90.degree., thereby clamping together the inner and outer packing boxes. With the use of such clamping devices having male and female members, the packaging may be facilitated, but there are defects in that the clamping device comprises two pieces and they are very complex in construction. Therefore, two kinds of dies or molds must be prepared with the result of an increased cost.